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The Sahara has not always been the arid, inhospitable place that it is today. Geological studies reveal that it has experienced considerably wetter periods, lasting for thousands of years, when the desert turned to savannah and lakes provided water for people and animals. The vast majority of these ancient lakes are now just dry relics, but they remain fertile sites for archaeological investigation. The authors and their colleagues have mounted multiple expeditions to the Libyan desert, using satellite imagery for guidance. Their work illuminates the geological history of the area and shows the ways in which ancient inhabitants coped with the changing climate.
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